There has been known a type of rotary device in which centrifugal elements are attached to a rotor rotated about a rotational axis. The rotary device exerts a function when a centrifugal force acts on each centrifugal element in rotation of the rotor. The rotary device described above is exemplified by a torque fluctuation inhibiting device.
For example, as described in Japan Laid-open Patent Application Publication No. 2017-53467, the torque fluctuation inhibiting device inhibits torque fluctuations when a centrifugal force acts on each centrifugal element. Detailedly, the torque fluctuation inhibiting device includes an inertia ring, centrifugal elements and cam mechanisms. The inertia ring is rotatable relative to a hub flange to which a torque is transmitted, and the centrifugal force acts on each centrifugal element in rotation of the hub flange and the inertia ring. Each cam mechanism includes a cam provided on the surface of each centrifugal element and a cam follower making contact with the cam.
When the hub flange and the inertia ring are circumferentially displaced by torque fluctuations, each cam mechanism is actuated in response to the centrifugal force acting on each centrifugal element. Then, each cam mechanism converts the centrifugal force into a circumferential force directed to reduce the displacement between the hub flange and the inertia ring. Torque fluctuations are inhibited by this circumferential force.
In the torque fluctuation inhibiting device described in Japan Laid-open Patent Application Publication No. 2017-53467, the hub flange is provided with recessed portions in the outer peripheral part thereof. The recessed portions are opened radially outward. The centrifugal elements are accommodated in the recessed portions, respectively, and are radially movable therein. Each recessed portion is defined by inner wall surfaces. Two of the inner wall surfaces face the circumferential direction, and function as guide surfaces in radial movement of each centrifugal element. Gaps are produced between the guide surfaces and each centrifugal element.
With the gaps produced between each centrifugal element and the guide surfaces, each centrifugal element is tilted or circumferentially moved during actuation of the torque fluctuation inhibiting device. The tilt and movement of each centrifugal element depend on the orientation of the circumferential force acting on each centrifugal element. When each centrifugal element is tilted or circumferentially moved, the profile of the cam provided on the surface of each centrifugal element is inevitably changed from a profile planned in design phase. This results in inability of stably obtaining a characteristic planned in design phase in the torque fluctuation inhibiting device.
Thus, the gaps produced between each centrifugal element and the guide surfaces pose a drawback that a characteristic of the rotary device cannot be stably obtained. In view of this, it is an object of the present invention to stabilize the characteristic of the rotary device.